Re: 2.6.8.1 Mis-detect CRDW as CDROM

[Marc Ballarin]

On Mon, 16 Aug 2004 14:03:06 +0100
Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> On Llu, 2004-08-16 at 13:38, Marc Ballarin wrote:
> > Due to the newly added command filtering, you now need to run cdrecord as
> > root. Since cdrecord will drop root privileges before accessing the drive,
> > setuid root won't help
> 
> cdrecord should be fine. k3b is issuing something not on the filter
> list.
> 
> > This patch restores the behaviour of previous kernels, security issues included:
> 
> Like allowing any user to erase your drive firmware. What you could do
> which is much more useful is printk the command byte that gets refused
> and see if you can pin down what commands are being blocked that
> are needed by K3B 
> 
> Alan
> 

cdrecord 2.01a28 wants:
when doing dev=/dev/dvd -atip:
OR
dev=/dev/cdrom blank=fast

0x46 0x55 0x1e 0x1 0x35

when trying to write:
0x46 0x55

dvd+rw-mediainfo wants:
0x46

k3b wants:
0x46 0x55 0xac

Those are all command I've seen so far:
0x1 REWIND
0x1e PREVENT ALLOW MEDIUM REMOVAL
0x35 SYNCHRONIZE_CACHE
0x46 ?
0x55 MODE SELECT(10)
0xac ERASE(12)

Here is the patch I've been using:

--- linux-2.6.8/drivers/block/scsi_ioctl.c.orig	2004-08-16 19:48:15.083524248 +0200
+++ linux-2.6.8/drivers/block/scsi_ioctl.c	2004-08-16 19:09:19.000000000 +0200
@@ -174,0 +175,2 @@
+	else	
+		printk(KERN_WARNING "FILTERED: %x \n", cmd[0]);
-
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